From one of the PDF documents that I downloaded from AMD, they give other reasoning besides having the +5V power ready for things like keyboard power-on function.
Power supplies will have exhaust fans in the rear that blow out hot air. The intake for these fans is pulling air from the innards of the case. What AMD recommends is that the intake fan be on the bottom of the PSU, so that it is positioned directly above the hot air coming off of the CPU. Some power supply units have their air intakes positioned facing the top IDE drive in your case, and therefore, are not most-efficiently pulling excess hot air surrounding your Athlon. Athlons have tended to run pretty hot, if you haven't already heard.
I have a 300W power supply, but it's not AMD approved. I put an additional Enermax fan on the back of my case to pull more air away from the CPU. That cost me about $8 which is a bit cheaper than replacing the PSU. I figure if my CPU overheats, it's not gonna happen within a year's time (OEM warranty=one year) so I won't be able to get it RMA'd anyway.
Look at this link from AMD:
http://www.amd.com/us-en/Processors/Tec ... 2_869_1039
It has lists of PDF files that you can download.
<font size=-1>[ This Message was edited by: jsbach11 on 2002-01-25 18:05 ]</font>